A Physics-Based Compact Direct-Current and Alternating-Current Model for AlGaN/GaN High Electron Mobility Transistors

A set of analytical models for the dc and small signal characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) are presented. A modified transferred-electron mobility model is adapted and a phenomenological low-field mobility model is developed. We calculate the channel charge considering the neutralization of donors and the contribution of free electrons in the AlGaN layer. The gate-to-source and gate-to-drain capacitances are obtained analytically, and the cut-off frequency is predicted. The models are implemented into the HSPICE simulator for the dc, ac and transient simulations and verified by experimental data for the first time. A high efficiency class-E GaN HEMT power amplifier is designed and simulated by the HSPICE to verify the applicability of our models.